Repair a Cracking Brick Chimney

Learn how to repair a cracking brick chimney. Find out how using an epoxy patching compound will help fix a brick chimney that's spalling or cracking.

LESLIE: William in Indiana is having some chimney situations. William, how can we help?

WILLIAM: Hi, we just bought a brick house – it’s a one-story Cape Cod; all brick – and we have some bad what I’ve been told is called spalling [1]…

TOM: OK.

WILLIAM: … on top of our chimney. Just, you know, sections of the brick are – well it’s one or two bricks where a chunk of the brick is actually popping out of the chimney.

TOM: Fairly common in an older house. What is it, like a 50-year-old Cape or something?

WILLIAM: Built in 1951.

TOM: OK. Yeah, so pretty close. (chuckles)

LESLIE: Sixty.

TOM: Fifty, sixty years old. Very common. What happens is as water gets into the brick and it freezes it kind of breaks apart the brick[2]; happens most commonly at the top few courses of brick and generally you have to do a number of things here. Number one, you have to make up a concrete mix to patch the brick and you can actually dye some epoxy patching compound[3] …

WILLIAM: OK.

TOM: … to match that brick so it’ll be red – I’m assuming it’s a red brick – and then repoint the mortar joints. But most importantly, the very top of the chimney is going to be a crown made of cement that goes from the liner to the outside edge of the brick chimney and I’m going to guess that that crown is cracked. They very, very commonly do and it needs to be either replaced or certainly those cracks in that top crown should be caulked because that will slow the water that’s getting down into that space and if you slow the water you’re going to slow that spawling effect and keep those bricks intact for as long as possible. But nothing too complicated; nothing terrible for you to have to worry about. Fairly normal wear and tear for a 50 to 60-year-old brick chimney.

WILLIAM: OK. So that chunk of brick that’s actually popping out, it’s not an entire brick; it’s just a rather large chunk. It’s like a four-inch, you know, long chunk.

TOM: (overlapping voices) If it’s clean – if it’s clean you may be able to mortar it back into place.

WILLIAM: OK.

TOM: If it’s really broken up then I would fill that kind of like you think of filling like a hole or a cavity and I would mix up a mortar mix [4]and I would tint it to match the brick. If you go to the home center or hardware store you’ll find out that there are concrete tints; they’re usually powder.

WILLIAM: Yeah.

TOM: I just did this not so long ago; repairing a brick step on my dad’s patio and I was able to mix it up very carefully to get a color that was fairly close to what was there. And it’s not going to match exactly but it’s better than having a gray patch on a red brick chimney.